JPWO2017104643A1 - Leak inspection apparatus and method - Google Patents

Abstract

If the sealing defect has the same size, the same leakage judgment result is obtained even if conditions such as temperature and pressure change. The leakage element 5 that generates a specified leakage under a specified temperature and pressure is communicated with the inspection path 19 to which the test pressure is supplied, and the element measurement leakage value from the leakage element 5 is measured by the leakage measuring means 33. . The actual measured leakage value from the inspection target 9 is actually measured by the leakage measuring means 33. The target measured leak value is converted into a specified condition converted leak value under the specified conditions based on the element measured leak value, and a leak is determined based on the specified condition converted leak value.

Description

  The present invention relates to a leakage inspection apparatus and method, and more particularly, to a leakage inspection apparatus and method using a leakage element that exhibits a constant leakage amount under specified temperature and pressure conditions.

  When determining the pass / fail of a workpiece (inspection object) by an air leak tester (leakage inspection device), “leakage amount” is generally adopted as a unit indicating the reference. Inside the air leak tester, a pressure drop (a pressure increase in the negative pressure or chamber method, but for the sake of brevity, the pressure method is described here) is measured. Previously, the threshold for pass / fail judgment was often specified by the magnitude of the drop pressure, but even if the same amount of leakage occurred, the pressure drop would change if the workpiece volume was different. Doing is taking root.

  Patent Document 1 (Japanese Patent Application Laid-Open No. 2012-112752) describes a leak element used for calibration and maintenance of an air leak tester. A leak element is connected to the leak detection path. The leakage element has a capillary tube. The leak element causes a constant leak from the capillary tube under specified temperature and pressure conditions.

JP2012-112752A

  However, the amount of leakage that flows through a narrow passage changes if the pressure at the entrance and exit of the passage changes. Moreover, it changes even if the temperature changes. That is, if the leak test conditions (mainly pressure and temperature) change, the amount of leak actually flowing changes. Therefore, if the leakage amount under a certain fixed condition is set as a threshold value, it cannot be said that the inspection is performed based on the same criterion when the pressure and temperature change.

ここで、
Ｑ： 流量（Ｐａ・ｍ^３／ｓ）
Ｄ： 管の内径（ｍ）
Ｌ： 導管の長さ（ｍ）
η： 気体の粘性係数（Ｐａ・ｓ）
Ｐ_１： 入口の圧力（Ｐａ）
Ｐ_２： 出口の圧力（Ｐａ）
である。Most of the range of gas leakage to be inspected by the air leak tester is in the viscous flow region. The Hagen-Poiseuille equation is a typical calculation formula for viscous flow (Equation 1).

here,
Q: Flow rate (Pa · m ³ / s)
D: Inner diameter of tube (m)
L: Length of conduit (m)
η: Viscosity coefficient of gas (Pa · s)
P ₁ : Inlet pressure (Pa)
P ₂ : outlet pressure (Pa)
It is.

As can be seen from Equation 1, parameters that change the flow rate Q (leakage amount) exist in addition to “holes”, that is, D and L indicating the properties of the sealing defect to be inspected. That is, the viscosity coefficient η of the gas varies depending on the temperature (the temperature to be inspected and the ambient temperature). The inlet pressure P ₁ (test pressure) may vary depending on the performance of the regulator. The outlet pressure P ₂ (atmospheric pressure) varies depending on weather conditions and regions. Further, the equation (1) is a calculation of the volume flow rate, and the gas passing through the leak passage is also subjected to the contraction / expansion effect accompanying the temperature change. For this reason, if the determination is made based on the actual flow rate, the inspection standard changes due to the change of the test conditions.

  The present invention has been made in view of such circumstances, and the purpose of the present invention is to provide a leak determination method that can obtain the same result even if conditions such as temperature and pressure change if the sealing defect has the same size. The purpose is to provide.

In order to solve the above-mentioned problems, the inventor has conceived to shift the criteria for leak determination from “actual leak” to “leak under specified conditions” and thus “size of sealing defect to be inspected”.
That is, the present invention is a leakage inspection method for inspecting leakage from an inspection object,
Based on the actual measured value of the leak from the reference leak hole that generates the specified leak under the specified temperature and pressure, the actual measured value of the leak from the inspection object is used as the virtual defect hole (virtual sealing defect) of the inspection object. It is converted to a hole dimension equivalent value corresponding to the size of the above, and leakage is determined based on the hole dimension equivalent value.
The value corresponding to the hole size becomes the same value if the size of the sealing defect is the same even if the test conditions such as temperature and pressure or the environmental conditions are changed. Thereby, the same leak determination result can be obtained.

The device of the present invention is a leakage inspection device for inspecting leakage from an inspection object,
A leakage detection path that has an inspection path connected to the inspection target, and that supplies test pressure from the inspection path to the inspection target;
A leakage element that is provided in the leakage detection path and generates a specified leakage (hereinafter referred to as “specified leakage value”) under a specified temperature and pressure (hereinafter referred to as “specified condition”);
Leakage measuring means provided in the leakage detection path;
Processing means, and the processing means comprises:
Element measurement operation for measuring leakage from the leaking element (hereinafter referred to as “element actual leakage value”) by the leakage measuring means;
An object measurement operation in which leakage from the inspection object (hereinafter referred to as “object measurement leakage value”) is actually measured by the leakage measurement unit;
The target measured leak value is converted into a specified condition converted leak value under the specified condition based on the element measured leak value, and a determination operation is performed to determine a leak based on the specified condition converted leak value. .
The prescribed condition converted leakage value is an example of a hole size equivalent value corresponding to the size of the virtual defect hole (virtual sealing defect) to be inspected, and even if conditions such as temperature and pressure change, If the size is the same, the value is the same. Thereby, the same leak determination result can be obtained.

The leak inspection apparatus includes an apparatus housing and an inspection unit in which the inspection object is arranged,
The apparatus housing is provided with the leakage measuring means and the processing means,
It is preferable that the inspection portion is provided with the arrangement portion to be inspected and the leakage element in proximity to each other.
As a result, the ambient temperature and the external pressure (outlet pressure) of the inspection target and the leaking element can be substantially matched with each other. As a result, the accuracy of the conversion can be improved.

The leak detection path includes a reference path including a reference container, and a valve means capable of communicating and blocking the reference path and the inspection path,
The leakage measuring means is a differential pressure gauge provided between the inspection path and the reference path;
It is preferable that the inspection path is released to the atmosphere after the measurement by the valve means, while the reference path and thus the reference container is maintained at a test pressure.
Thereby, the influence by the adiabatic compression or the like of the reference container can be eliminated. In addition, the following effects are expected to be secondary.
(1) At the timing when intense flow occurs in the pressurization or exhaust process, the sensor part is shut off, and at the timing communicating with the sensor, there is almost no flow at the same pressure (test pressure) as the workpiece. Foreign matter does not enter the sensor.
(2) Unlike the work (inspection object), the master (reference container) repeatedly pressurizes and evacuates. For this reason, when used in a humid area, condensed water may accumulate inside, leading to a failure of the tester, but this method can be avoided.
(3) Since the stress due to pressurization / exhaust of the differential pressure sensor (leakage measuring means) is reduced, improvement in durability is expected.

A test pressure measuring means for measuring the test pressure;
An external pressure measuring means for measuring the leakage element or the external pressure of the inspection object;
Temperature measuring means for measuring the ambient temperature of the leakage element or the inspection object, and the processing means, the measured values of the test pressure measuring means, the external pressure measuring means and the temperature measuring means during the object actual measurement operation, and It is preferable to calculate a conversion coefficient for converting the target measured leak value into the specified condition converted leak value based on the reference leak hole size coefficient determined by the size of the reference leak hole of the leak element and the specified leak value.
Thereby, according to environmental conditions, such as ambient temperature at the time of actual measurement of an inspection object, external pressure, etc., object actual measurement leak value can be appropriately converted into regulation condition conversion leak value.

The method of the present invention is a leakage inspection method for inspecting leakage from an inspection object,
A leakage element that generates a specified leakage (hereinafter referred to as a “specified leakage value”) under a specified temperature and pressure (hereinafter referred to as “specified conditions”) is communicated with a leakage detection path that supplies a test pressure, and An element actual measurement process for actually measuring an element actual leakage value from the leaking element;
An object measurement step of connecting an inspection object with the leak detection path and actually measuring an object measurement leakage value from the inspection object;
A determination step of converting the target actual leakage value into a value under the specified condition based on the element actual leakage value, and determining leakage based on the converted value;
It is provided with.
The specified condition-converted leakage value is a value corresponding to a hole size, and even if conditions such as temperature and pressure are changed, the same value is obtained if the size of the sealing defect is the same. Thereby, the same leak determination result can be obtained.

It is preferable that the prescribed leakage value is 0.8 to 1.2 times the leakage determination threshold value of the inspection target.
Thereby, the deviation of the variation characteristic with respect to the temperature and pressure between the leakage element and the inspection object can be minimized.
It is preferable to use an inspection object that has a leakage close to the leakage threshold value of the leakage element in the specified state.

Sequentially determine leaks for multiple inspection targets,
When the actual leakage value of the inspection object determined as the subsequent non-defective product is increased or decreased by a predetermined ratio or more with respect to the actual leakage value of the inspection object determined as the non-defective product in the first order, It is preferable to update the element actual leakage value.
Thereby, when temperature and pressure fluctuate greatly, the accuracy of leakage determination can be ensured by resetting the element actual leakage value.
The first-order target actual measurement leakage value may be an actual measurement value of a non-defective product inspection target immediately after acquisition of the previous element actual measurement leakage value.

Calculate a conversion factor based on the specified leakage value and the element actual leakage value,
It is preferable to convert the target actual measurement leakage value into a specified condition conversion leakage value based on the conversion coefficient. The conversion coefficient is a coefficient for converting an actual measurement value to a value under a specified condition.

A conversion coefficient is calculated based on the test pressure, the external pressure and the ambient temperature during the target actual measurement process, and the standard leak hole size coefficient determined by the size of the reference leak hole of the leak element and the specified leak value,
It is preferable to convert the target actual measurement leakage value into a specified condition conversion leakage value based on the conversion coefficient.
Thus, each time an inspection object is inspected, a conversion coefficient reflecting environmental conditions such as temperature and pressure at the time of the inspection can be calculated, and the actual measured leakage value can be converted into a prescribed condition conversion leakage value. Therefore, if the sealing defect has the same size, even if conditions such as temperature and pressure change, the same leak determination result can be obtained reliably, and the reliability of the leak determination can be further improved. .

It is preferable to calculate the reference leak hole size coefficient based on the element actual leakage value, the test pressure, the external pressure, and the ambient temperature in the element actual measurement step.
As a result, even if the size (diameter, length, etc.) of the reference leak hole is uncertain or the diameter is not constant, the reference leak hole size factor can be set appropriately, and in turn converted. Can improve the accuracy.

  According to the present invention, if the sealing defect has the same size, the same leak determination result can be obtained even if conditions such as temperature and pressure change.

FIG. 1 is a circuit diagram of a leakage inspection apparatus according to the first embodiment of the present invention. FIG. 2 is a circuit diagram of a leakage inspection apparatus according to the second embodiment of the present invention. FIG. 3 is a circuit diagram of a leakage inspection apparatus according to the third embodiment of the present invention. FIG. 4 is a time chart of the operation of the leakage inspection apparatus according to the third embodiment. FIG. 5 is a circuit diagram of a leakage inspection apparatus according to the fourth embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
As shown in FIG. 1, the leak inspection apparatus 1 includes a leak detection path 10, a processing means 3 (control means), and a leak element 5. The leak detection path 10 includes a common path 11, a reference path 18, and an inspection path 19. A common path 11 extends from the pressure source 2. In the common path 11, a pressure regulating valve 21, a pressure gauge 31 (test pressure measuring means), and a pressurized exhaust valve 22 formed of a three-way valve are sequentially provided from the pressure source 2 side.

A reference path 18 and an inspection path 19 are branched from the common path 11. A reference shut-off valve 28 is provided in the reference path 18. The downstream end of the reference path 18 is connected to the reference container 8. An inspection cutoff valve 29 is provided in the inspection path 19. The downstream end of the inspection path 19 is connected to the inspection object 9. A differential pressure gauge 33 (leakage measuring means) is provided between the reference path 18 and the inspection path 19 downstream of the shutoff valves 28 and 29.
The valves 21 to 29 constitute valve means.

Further, the calibration path 15 extends from the inspection path 19 downstream (inspected 9 side) from the inspection cutoff valve 29. A calibration valve 25 is provided in the calibration path 15. A leak element 5 is provided at the downstream end of the calibration path 15. By opening / closing the calibration valve 25, the leak element 5 is brought into contact with and separated from the leak detection path 10. The leakage element 5 is an element expected to behave in the same manner as the “hole” (defect) to be inspected, and is priced under a predetermined temperature and pressure condition (regulated condition). That is, the leak element 5 has a reference leak hole 5a, and generates a specified leak amount Q _5S (specified leak value) under specified temperature and pressure conditions. On the outer surface or the like of the leakage element 5, the temperature, pressure, and specified leakage amount _Q5S of specified conditions are written.

Furthermore, the leakage inspection apparatus 1 is provided with a processing means 3.
The processing means 3 includes a microcomputer, drive circuits for the valve means 21 to 29, and the like. The processing means 3 controls the operations of the valve means 21 to 29 and the like of the leak inspection apparatus 1 and further performs a leak determination process. In the memory 3m (storage means) of the microcomputer, in addition to a sequence program for leak inspection, a leak determination threshold value Q _9B (Pa · m ³ / s) of the inspection object 9 and a specified leak amount Q _5S ( Pa · m ³ / s), the volume V (m ³ ) of the inspection object 9, and the like data necessary for leak determination are stored.

A leak inspection method using the leak inspection apparatus 1 will be described.
The specified leakage amount _Q5S of the leakage element 5 is stored in the processing means 3 in advance. Further, a threshold value for leak determination of the inspection object 9 is set and stored in the processing means 3.
Preferably, the leakage element 5 is selected such that the specified leakage amount Q _5S is as close as possible to the leakage determination threshold value of the inspection object 9. The specified leakage amount _Q5S is preferably 0.8 to 1.2 times the leakage determination threshold value of the inspection object 9.
Further, it is preferable that the specified conditions (specified temperature and specified pressure) of the leak element 5 are as close as possible to the test conditions (temperature and pressure) of the leakage test site of the inspection object 9.

  As a result, at least near the test conditions, the deviation of the variation characteristics with respect to the temperature and pressure between the leakage element 5 and the inspection object 9 can be minimized.

<Element measurement>
A non-defective non-defective product inspection object 9 is connected to the inspection path 19.
The common path 11, the reference path 18, and the inspection path 19 are communicated by the pressurized exhaust valve 22. Further, the shutoff valves 28 and 29 are opened. As a result, the air pressure from the pressure source 2 is reduced to the test pressure at the pressure regulating valve 21. This test pressure is introduced from the reference path 18 to the reference container 8 and from the inspection path 19 to the non-leakage non-defective product inspection object 9.

  Next, the shutoff valves 28 and 29 are closed. As a result, the reference path 18 on the reference container 8 side from the reference cutoff valve 28 and the inspection path 19 on the inspection object 9 side from the inspection cutoff valve 29 form a closed space independent of each other.

ここで、Δｔは、実測圧力変化ΔＰ_５Ｒの検出時間（ｓ）である。Next, the leak element 5 is connected to the leak detection path 10 by opening the calibration valve 25. As a result, leakage occurs from the leakage element 5, and a pressure difference is generated between the reference path 18 and the inspection path 19 downstream from the shutoff valves 28 and 29. This pressure change ΔP _5R is detected by the differential pressure gauge 33. The actual measurement data ΔP _5R of the pressure change is input to the processing means 3. The processing unit 3 calculates the actual leakage amount Q _5R (element actual leakage value) from the leakage element 5 by performing the calculation of the following expression (2).

Here, Δt is the detection time (s) of the actually measured pressure change ΔP _5R .

<Conversion coefficient calculation>
Furthermore, the processing means 3 calculates | requires the conversion factor k according to following Formula (3), and memorize | stores this in the memory 3m.

Note that the element actual leakage amount Q _5R (or the actual pressure change ΔP _5R ) is preferably a value obtained by removing the fluctuation due to the temperature change due to the introduction of the test pressure, the expansion of the inspection object 9, and the like. As a removal method, a known method such as a mastering method (see JP-A-9-33381), a fitting method (see JP-A-2004-062011), a linear fitting method (see JP-A-2012-255687), etc. Can be applied.

<Target measurement>
After that, leakage inspection is performed on the actual inspection object 9.
Specifically, the actual inspection object 9 is connected to the inspection path 19.
The common path 11, the reference path 18, and the inspection path 19 are communicated by the pressurized exhaust valve 22. Further, the shutoff valves 28 and 29 are opened. As a result, the air pressure from the pressure source 2 is reduced to the test pressure at the pressure regulating valve 21. The test pressure is introduced from the reference path 18 to the reference container 8 and is introduced from the inspection path 19 to the inspection object 9.

  Next, the shutoff valves 28 and 29 are closed. As a result, the reference path 18 on the reference container 8 side from the reference cutoff valve 28 and the inspection path 19 on the inspection object 9 side from the inspection cutoff valve 29 form a closed space independent of each other.

つまり、素子実測漏れ量Ｑ_５Ｒ（＝Ｑ_５Ｓ／ｋ）に基づいて、対象実測圧力変化ΔＰ_９Ｒに対応する対象実測漏れ量Ｑ_９Ｒを規定条件下での値に換算する。規定条件換算漏れ値Ｑ_９Ｓは、検査対象９の仮想欠陥孔（仮想の密封欠陥）の大きさに相当する孔寸法相当値であり、温度や圧力等の環境条件が変わっても、密封欠陥の大きさが同じであれば、同じ値になる。Next, the time difference ΔP _9R (measured pressure change) of the pressure difference between the reference path 18 and the inspection path 19 and the reference container 8 and the inspection object 9 is detected by the differential pressure gauge 33. The actually measured pressure change ΔP _9R is input to the processing means 3. The processing means 3 calculates the specified condition converted leakage value Q _9S by performing the calculation of the following expression (4) (converting step). The specified condition converted leakage value Q _9S (or actually measured pressure change ΔP _9R ) is preferably a value obtained by removing the variation due to the temperature change due to the introduction of the test pressure or the expansion of the inspection object 9 in the same manner as described above. .

That is, based on the element actual leakage amount Q _5R (= Q _5S / k), the target actual leakage amount Q _9R corresponding to the target actual pressure change ΔP _9R is converted into a value under a specified condition. The specified condition equivalent leakage value _Q9S is a hole dimension equivalent value corresponding to the size of the virtual defect hole (virtual sealing defect) of the inspection object 9, and even if environmental conditions such as temperature and pressure change, the sealing defect If the size is the same, the value is the same.

<Leakage determination>
Next, the leakage determination is performed based on the specified condition converted leakage value Q _9S (hole size equivalent value).
Specifically, if the specified condition converted leakage value Q _9S is within the threshold value Q _9B , the inspection object 9 is determined to be a non-defective product (no leakage). If the specified condition equivalent leakage value Q _9S exceeds the threshold value Q _9B , the inspection object 9 is determined to be defective (leak).
As a result, if the sealing defect has the same size, the same leakage determination result can be obtained even if conditions such as temperature and pressure change.

After completion of the measurement, the shutoff valves 28 and 29 are opened, and the pressurized exhaust valve 22 is set to the atmospheric release position, so that the test pressure in the inspection path 19 and the reference path 18 and consequently the reference container 8 and the inspection object 9 is discharged. .
Thereafter, similarly, a plurality of inspection objects 9 are sequentially inspected for leaks.

Processing means 3, by storing the measured leak amount Q _9R inspected 9 is non-defective determination of these inspected 9 sequentially memory 3m, monitoring the transition of the actual leak amount Q _9R (aging).
Then, the measured leak amount Q _9R inspected 9 is determined earlier order of good, found leak amount Q _9R inspected 9 is determined postorder of good product, a predetermined ratio (for example, 3% to 10%) When the number is increased or decreased, the element measurement process is repeated. As a result, when the fluctuation range from the previous acquisition of the element measured leakage amount _Q5R is increased due to the gradual change in temperature and pressure, the element measured leakage amount _{Q5R and} thus the conversion coefficient k is changed to the temperature after the change. And can be updated to a value corresponding to the pressure. Thereafter, using the updated element actual leakage amount Q _5R or the conversion coefficient k, the specified condition converted leakage value Q _9S is calculated to determine the leakage. As a result, the accuracy of the leak determination can be ensured. Moreover, as long as the temperature and pressure does not change suddenly increases, there is no need to update the element measured leak amount Q _5R frequently measured to be avoided complication.
Further, according to the first embodiment, it is not necessary to provide a temperature sensor, a pressure sensor, and a monitoring unit for the measurement values of these sensors, and it is possible to prevent an increase in product cost.

Next, another embodiment of the present invention will be described. In the following embodiments, the same reference numerals are given to the drawings for the same configurations as those already described, and the description thereof is omitted.
[Second Embodiment]
As shown in FIG. 2, the leak inspection apparatus 1B according to the second embodiment includes an apparatus housing 1a and an inspection unit 1b.
The apparatus housing 1a includes a pressure source 2, a processing unit 3, a portion from the connection between the pressure source 2 in the leak detection path 10 to the differential pressure gauge 33, and pneumatic elements 21 and 22 disposed in the portion. , 28, 29, 31, 33 are stored. Although not shown, the apparatus housing 1a is further provided with a manual operation of the valve means 21 to 29 in addition to an input unit such as a monitor and a touch panel.

  The inspection unit 1b is provided with a reference container 8, an inspection object placement unit 9x, a leakage element 5, and a calibration valve 25. The inspection object 9 is arranged in the inspection object arrangement unit 9x. A reference path 18 extends from the apparatus housing 1 a and is introduced into the inspection unit 1 b, and its tip is connected to the reference container 8. An inspection path 19 extends from the apparatus housing 1 a and is introduced into the inspection unit 1 b, and a tip portion (inspection target connection portion) thereof is connected to the inspection target 9. The calibration path 15 extends from the apparatus housing 1 a and is introduced into the inspection unit 1 b, and the leakage element connection portion at the tip thereof is connected to the leakage element 5. A calibration valve 25 is interposed on the calibration path 15 in the inspection unit 1b. The calibration valve 25 is remotely operated by the processing means 3 of the apparatus housing 1a.

The inspection unit 1b is provided with the inspection target arrangement unit 9x and the leakage element 5 in close proximity to each other. That is, the leakage element 5 is arranged near the inspection object 9.
As a result, the leakage element 5 can be placed under substantially the same temperature and pressure conditions as the inspection object 9 and can be subjected to the same variation as the inspection object 9 as much as possible. As a result, it is possible to ensure the accuracy of the leak determination based on the actually measured leak amount Q _5R of the leak element 5.
In the leak inspection apparatus 1B, the reference container 8 may be disposed in the apparatus housing 1a.

[Third Embodiment]
FIG. 3 shows a leak inspection apparatus 1C according to the third embodiment of the present invention. In the leakage inspection apparatus 1C, electromagnetic on-off valves 41 to 47 are provided as valve means. A flowchart of the on / off operation of these on-off valves 41 to 47 is shown in FIG.
In the pressurizing step, the test pressure is introduced to the inspection object 9 by opening the valve 44 and closing the valve 42. On the other hand, a test pressure is always introduced into the reference container 8 via valves 45 and 47.
In the equilibration step, the reference container 8 and the inspection object 9 are communicated via the communication path 17 by closing the valve 43, opening the valve 44, and closing the valve 45.
Subsequently, the reference container 8 and the inspection object 9 are blocked by closing the valve 47.
Then, the differential pressure is detected by the differential pressure gauge 33 (measurement of the actually measured leakage amount _Q9R ).

After the detection step, the valve 41 is closed, the valves 42 and 43 are opened, the valve 44 is closed, and the valves 45 and 47 are opened. As a result, the inspection object 9 is released to the atmosphere. On the other hand, the reference container 8 is maintained at the test pressure without being released to the atmosphere.
Thereby, the influence by the adiabatic compression of the reference container 8 can be eliminated.
The calibration valve 46 is always closed.
The air passage including the valves 44 to 47, the differential pressure gauge 33, the reference container 8 and the like is incorporated in a metal measurement block 4 indicated by a two-dot chain line in FIG.

[Fourth Embodiment]
FIG. 5 shows a leak inspection apparatus 1D according to the fourth embodiment of the present invention. The leak inspection apparatus 1D is further provided with a temperature measuring means 6 and an atmospheric pressure measuring means 32 (external pressure measuring means) in the leak inspection apparatus 1C of the third embodiment (FIG. 4). The inspection object 9 and the leakage element 5 are arranged close to each other. The temperature measuring means 6 and the atmospheric pressure measuring means 32 are arranged near the inspection object 9 and the leak element 5.

The temperature measurement means 6 measures the temperature T ₆ (° C. or K) of the leakage inspection apparatus 1D, particularly in the periphery of the inspection object 9 and the leakage element 5.
Further, the atmospheric pressure measuring means 32 measures the external pressure of the inspection object 9 and the leakage element 5, that is, the absolute pressure P ₃₂ (Pa-abs.) Of the atmospheric pressure around the inspection object 9 and the leakage element 5. Absolute pressure P ₃₂ atmospheric pressure corresponds to the external pressure (the outlet pressure of the sealing defect) or external pressure leakage element 5 to be inspected 9 (the outlet pressure of the leaking hole 5a).
Two atmospheric pressure measuring means 32 may be provided separately near the inspection object 9 and near the leak element 5. Two temperature measuring means 6 may be provided separately near the inspection object 9 and near the leakage element 5.

In the leak inspection apparatus 1D, the leak inspection is performed as follows.
<Element measurement process>
In the element actual measurement step, the element actual pressure change ΔP _5R is measured by the differential pressure gauge 33 (leakage measuring means), and the element actual leakage value Q _5R is derived according to Equation 2.
In addition, the test pressure measuring means 31 measures the test pressure P ₃₁ (Pa), the atmospheric pressure measuring means 32 measures the atmospheric absolute pressure P ₃₂ (Pa-abs.), And the temperature measuring means 6 measures the ambient temperature T. ₆ Measure (K). Hereinafter, the measured values P ₃₁ , P ₃₂ , and T ₆ at the time of the element actual measurement process are denoted as P _31A , P _32A , and T _6A by adding A to the end of the suffix.

なお、式５における試験圧Ｐ_３１Ａは、絶対圧力（Ｐａ-abs.）である。試験圧測定手段３１がゲージ圧計である場合には、試験圧測定手段３１の測定値に大気圧実測値Ｐ_３２Ａを加算することで絶対圧力Ｐ_３１Ａに換算する。
Ｔ_Ｓは、規定条件の温度（Ｋ）であり、例えばＴ_Ｓ＝２９６．１５Ｋ（＝２３℃）である。
η_６Ａは、実測温度Ｔ_６Ａ（Ｋ）における気体（空気）の粘性係数（Ｐａ・ｓ）である。例えば２０℃（＝２９３．１５Ｋ）における空気の粘性係数は、１８．２×１０^−５（Ｐａ・Ｓ）であるから、サザランドの式によれば、以下の関係が成り立つ。

Ｃは、サザランド定数であり、空気の場合、Ｃ＝１１７である。According to Hagen-Poiseuille's law (Equation 1), the following relationship is established among these values Q _5R , P _31A , P _32A , and T _6A .

In addition, the test pressure _P31A in Formula 5 is an absolute pressure (Pa-abs.). When the test pressure measuring means 31 is a gauge pressure gauge, the atmospheric pressure actual measurement value P _32A is added to the measured value of the test pressure measuring means 31 to convert to the absolute pressure P _31A .
T _S is the temperature (K) of the specified condition, for example, T _S = 296.15 K (= 23 ° C.).
η _6A is a viscosity coefficient (Pa · s) of gas (air) at the actually measured temperature T _6A (K). For example, since the viscosity coefficient of air at 20.degree. C. (= 293.15 K) is 18.2 × 10 ⁻⁵ (Pa · S), the following relationship is established according to the Sutherland equation.

C is the Sutherland constant, and in the case of air, C = 117.

Ｄ_５は、漏れ素子５の基準漏れ孔５ａの直径である。Ｌ_５は、漏れ素子５の基準漏れ孔５ａの長さである。要するに、基準漏れ孔寸法係数Ａは、基準漏れ孔５ａの大きさを示す係数であり、具体的には、基準漏れ孔５ａの直径Ｄ_５の４乗に比例し、基準漏れ孔５ａの長さＬ_５に反比例する。A in the first term on the right side of Equation 5 is a reference leakage hole size coefficient determined by the size (D ₄ , L ₅ ) of the reference leakage hole 5a of the leakage element 5, and is, for example, as follows from Hagen-Poiseuille's law (Equation 1) Can be defined by an expression.

D ₅ is the diameter of the reference leak hole 5 a of the leak element 5. L ₅ is the length of the reference leak hole 5 a of the leak element 5. In short, the reference leak pore size factor A is a coefficient indicating the magnitude of the reference leak hole 5a, specifically, proportional to the fourth power of the diameter D ₅ of the reference leak hole 5a, the reference leak hole 5a length It is inversely proportional to L _5.

基準漏れ孔５ａの直径Ｄ_４及び長さＬ_４は、不明であったり製造誤差があったりして、不確かな場合がある。基準漏れ孔５ａの長さ方向の場所によって直径Ｄ_４が一定していなかったり断面が真円ではなかったりする場合もある。そのような場合を考慮して、第４実施形態における素子実測工程では、式８にＱ_５Ｒ、Ｐ_３１Ａ、Ｐ_３２Ａ及びＴ_６Ａの測定値を当てはめることで、基準漏れ孔寸法係数Ａを算出する。これによって、基準漏れ孔５ａの直径Ｄ_４及び長さＬ_４が不確かであったり、直径Ｄ_４が一定でなかったりしても、基準漏れ孔寸法係数Ａを適確に設定することができる。基準漏れ孔寸法係数Ａは、メモリ３ｍに記憶させておく。Further, the reference leak hole size factor A is also expressed by the following equations from Equations 5 and 6.

Reference leak pore 5a diameter D ₄ and a length L ₄ of the unknown was or was or have manufacturing errors, in some cases uncertain. In some cases the reference leak hole 5a in the longitudinal direction of the cross section may not have a constant diameter D ₄ by location or not a perfect circle. In consideration of such a case, in the element actual measurement process in the fourth embodiment, the reference leak hole size coefficient A is calculated by applying the measured values of Q _5R , P _31A , P _32A and T _6A to Equation 8. . As a result, even if the diameter D ₄ and the length L ₄ of the reference leak hole 5a are uncertain or the diameter D ₄ is not constant, the reference leak hole size factor A can be set appropriately. The reference leak hole size coefficient A is stored in the memory 3m.

The element measurement step, that is, the calculation step of the reference leak hole size coefficient A may be performed periodically at a predetermined time, such as at the start of work in the morning or afternoon, for example, when environmental conditions such as temperature and pressure change greatly. You may go irregularly.
If the diameter D ₄ and the length L _{5 of the} reference leak hole 5a are correctly known, the reference leak hole size coefficient A may be calculated using Equation 7.

<Target measurement process>
When inspecting the actual inspection object 9, the differential pressure change ΔP _9R is measured by the differential pressure gauge 33, and the actual measured leakage value Q _9R is derived according to Equation 9.

In addition, the test pressure measuring means 31 measures the test pressure P ₃₁ (Pa), the atmospheric pressure measuring means 32 measures the atmospheric absolute pressure P ₃₂ (Pa-abs.), And the temperature measuring means 6 measures the ambient temperature T. ₆ Measure (K). Hereinafter, each measured value P ₃₁ , P ₃₂ , T ₆ at the time of the target actual measurement process is denoted as P _31B , P _32B , T _6B by adding B at the end of the subscript.

式１０における試験圧Ｐ_３１Ｂは、絶対圧力（Ｐａ-abs.）である。試験圧測定手段３１がゲージ圧計である場合には、試験圧測定手段３１の測定値に大気圧実測値Ｐ_３２Ｂを加算することで絶対圧力Ｐ_３１Ｂに換算する。
η_６Ｂは、実測温度Ｔ_６Ｂ（Ｋ）における気体（空気）の粘性係数（Ｐａ・ｓ）であり、例えば２０℃（＝２９３．１５Ｋ）における空気の粘性係数１８．２×１０^−５（Ｐａ・Ｓ）と、サザランドの式とから、以下の関係が成り立つ。

According to Hagen-Poiseuille's law (Equation 1), the following relationship holds as in Equation 5.

The test pressure P _31B in Equation 10 is an absolute pressure (Pa-abs.). When the test pressure measurement means 31 is a gauge pressure gauge, the atmospheric pressure actual measurement value P _32B is added to the measurement value of the test pressure measurement means 31 to convert to the absolute pressure P _31B .
η _6B is the viscosity coefficient (Pa · s) of gas (air) at the actually measured temperature T _6B (K). For example, the viscosity coefficient of air at 20.degree. C. (= 293.15 K) is 18.2 × 10 ⁻⁵ (Pa The following relationship is established from S) and Sutherland's formula.

したがって、検査対象９の実測時における測定値Ｐ_３１Ｂ、Ｐ_３２Ｂ及びＴ_６、並びに漏れ素子５に関する基準漏れ孔寸法係数Ａ及び規定漏れ値Ｑ_５Ｓに基づいて、換算係数ｋを適確に求めることができる。この換算係数ｋに基づき、下式の演算を行なうことで、対象実測漏れ値Ｑ_９Ｒを規定条件換算漏れ値Ｑ_９Ｓに換算する（換算工程）。

By applying Expressions 10 and 11 to the left side and the middle side of Expression 3, the following expression is derived.

Therefore, the conversion coefficient k is accurately obtained based on the measured values P _31B , P _32B and T ₆ at the time of actual measurement of the inspection object 9, and the reference leakage hole size coefficient A and the specified leakage value Q _5S regarding the leakage element 5. Can do. Based on the conversion coefficient k, the target actual measurement leakage value Q _9R is converted into the specified condition conversion leakage value Q _9S by performing the following calculation (conversion step).

Then, the sealing property of the inspection object 9 is determined based on the specified condition converted leakage value _Q9S . That is, if Q _9S is equal to or smaller than the threshold value, the inspection object 9 is determined as a non-defective product (no leakage). If Q _9S exceeds the threshold value, the inspection object 9 is determined to be defective (leak).
According to the leak inspection apparatus 1D, every time the inspection object 9 is inspected, the conversion factor k reflecting the environmental conditions at the time of the inspection is calculated, and the target actual measurement leakage value Q _9R can be converted into the specified condition conversion leakage value Q _9S. . Therefore, if the sealing defect has the same size, even if conditions such as temperature and pressure change, the same leak determination result can be obtained reliably, and the reliability of the leak determination can be further improved. .
Further, for the reference leak pore size factor A used for calculating the conversion factor k, by reviewing regularly or irregularly, it is possible to enhance the proper確性Conversion to define conditions in terms leak value Q _9S.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, the leakage determination is not limited to the flow rate, and the leakage determination may be performed based on a differential pressure or a direct pressure.
The pressure source 2 is not limited to a positive pressure source such as an air compressor, and may be a negative pressure source such as a vacuum pump.
The present invention is not limited to an air leak test, and can be applied to a helium leak test, a hydrogen leak test, and other various leak tests.

  The present invention can be applied to quality determination of sealed products.

1, 1B, 1C, 1D Leakage inspection device 1a Device housing 1b Inspection unit 2 Pressure source 3 Processing means (control means)
3m memory (storage means)
4 Measurement Block 5 Leak Element 5a Reference Leakage Hole 6 Temperature Measuring Means 8 Reference Container 9 Inspection Object 10 Leakage Detection Path 11 Common Path 15 Calibration Path 18 Reference Path 19 Inspection Path 21 Pressure Adjustment Valve 22 Three-way Valve 25 Calibration Valve 28 Reference Shutoff Valve 29 Inspection shut-off valve
31 Pressure gauge (Test pressure measuring means)
32 Atmospheric pressure measuring means (external pressure measuring means)
33 Differential pressure gauge (leakage measuring means)
A Reference leak hole size factor k Conversion factor P _31A Actual test pressure value during _31A element actual measurement process P _31B Actual test pressure value during target actual measurement process P _32A Actual atmospheric pressure value during actual measurement process (external pressure actual value)
_P32B target actual measurement value during actual measurement process (external pressure actual measurement value)
ΔP _5R element actual pressure change (element actual leakage value)
ΔP _9R target measured pressure change Q _5S specified leakage amount (specified leakage value)
Q _5R element actual leakage amount (element actual leakage value)
Q _9R target measured leak amount (target measured leak value)
Q _9S defined conditions in terms leak value Q _9B inspected ambient temperature measured value Ts defined conditions temperature during ambient temperature measured value T _6B target actual process during the threshold T _6A elements measured process of leakage judgment

The temperature measurement means 6 measures the temperature T ₆ (° C. or K) of the leakage inspection apparatus 1D, particularly in the periphery of the inspection object 9 and the leakage element 5.
Further, the atmospheric pressure measuring means 32 measures the external pressure of the inspection object 9 and the leakage element 5, that is, the absolute pressure P ₃₂ (Pa-abs.) Of the atmospheric pressure around the inspection object 9 and the leakage element 5. Absolute pressure P ₃₂ atmospheric pressure corresponds to the external pressure (the outlet pressure of the sealing defect) or external pressure leakage element 5 to be inspected 9 (the outlet pressure of the leaking hole 5a).
Two atmospheric pressure measuring means 32 may be provided separately near the inspection object 9 and near the leak element 5. Two temperature measuring means 6 may be provided separately near the inspection object 9 and near the leakage element 5.

Claims (11)

A leakage inspection device for inspecting leakage from an inspection object,
A leakage detection path that has an inspection path connected to the inspection target, and that supplies test pressure from the inspection path to the inspection target;
A leakage element that is provided in the leakage detection path and generates a specified leakage (hereinafter referred to as “specified leakage value”) under a specified temperature and pressure (hereinafter referred to as “specified condition”);
Leakage measuring means provided in the leakage detection path;
Processing means, and the processing means comprises:
Element measurement operation for measuring leakage from the leaking element (hereinafter referred to as “element actual leakage value”) by the leakage measuring means;
An object measurement operation in which leakage from the inspection object (hereinafter referred to as “object measurement leakage value”) is actually measured by the leakage measurement unit;
The target measured leak value is converted into a specified condition converted leak value under the specified condition based on the element measured leak value, and a determination operation is performed to determine a leak based on the specified condition converted leak value. Leak inspection device. Including an apparatus housing and an inspection unit in which the inspection object is disposed;
The apparatus housing is provided with the leakage measuring means and the processing means,
The leakage inspection apparatus according to claim 1, wherein the inspection unit is provided with an arrangement portion to be inspected and the leakage element in proximity to each other. The leak detection path includes a reference path including a reference container, and a valve means capable of communicating and blocking the reference path and the inspection path,
The leakage measuring means is a differential pressure gauge provided between the inspection path and the reference path;
The leak inspection apparatus according to claim 1 or 2, wherein the inspection path is released to the atmosphere after the measurement by the valve means, while the reference path and thus the reference container is maintained at a test pressure. A test pressure measuring means for measuring the test pressure;
An external pressure measuring means for measuring the leaking element or the external pressure to be inspected;
Temperature measuring means for measuring the ambient temperature of the leakage element or the inspection object, and the processing means, the measured values of the test pressure measuring means, the external pressure measuring means and the temperature measuring means during the object actual measurement operation, and Based on a reference leak hole size coefficient determined by the size of the reference leak hole of the leak element and the specified leak value, a conversion coefficient for calculating the target measured leak value into the specified condition converted leak value is calculated. The leak inspection apparatus according to any one of claims 1 to 3. A leakage inspection method for inspecting leakage from an inspection object,
A leakage element that generates a specified leakage (hereinafter referred to as a “specified leakage value”) under a specified temperature and pressure (hereinafter referred to as “specified conditions”) is communicated with a leakage detection path that supplies a test pressure, and An element actual measurement process for actually measuring an element actual leakage value from the leaking element;
An object measurement step of connecting an inspection object with the leak detection path and actually measuring an object measurement leakage value from the inspection object;
A determination step of converting the target actual measured leak value into a specified condition converted leak value under the specified condition based on the element measured leak value, and determining a leak based on the specified condition converted leak value;
A leak determination method characterized by comprising:   6. The leak determination method according to claim 5, wherein the specified condition-converted leak value is 0.8 to 1.2 times a leak determination threshold value of the inspection target. Sequentially determine leaks for multiple inspection targets,
When the actual leakage value of the inspection object determined as the subsequent non-defective product is increased or decreased by a predetermined ratio or more with respect to the actual leakage value of the inspection object determined as the non-defective product in the first order, The leak determination method according to claim 5 or 6, wherein the element actual leak value is updated. Calculate a conversion factor based on the specified leakage value and the element actual leakage value,
The leak determination method according to any one of claims 5 to 7, wherein the target measured leak value is converted into a specified condition-converted leak value based on the conversion coefficient. A conversion coefficient is calculated based on the test pressure, the external pressure and the ambient temperature during the target actual measurement process, and the standard leak hole size coefficient determined by the size of the reference leak hole of the leak element and the specified leak value,
The leak determination method according to claim 5, wherein the target measured leak value is converted into a specified condition-converted leak value based on the conversion coefficient.   The leak determination method according to claim 9, wherein the reference leak hole size coefficient is calculated based on an element actual measurement leak value, a test pressure, an external pressure, and an ambient temperature in the element actual measurement step. A leakage inspection method for inspecting leakage from an inspection object,
Based on the actual measured value of the leak from the reference leak hole that generates the specified leak under the specified temperature and pressure, the actual measured value of the leak from the inspection object corresponds to the size of the virtual defect hole of the inspection object. Converted to the equivalent hole size,
Leak determination method, wherein leakage is determined based on the hole size equivalent value.

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